1. Field of the Disclosure
Embodiments of the disclosure relate to an image display device capable of selectively implementing a two-dimensional plane image (hereinafter referred to as ‘2D image’) and a three-dimensional stereoscopic image (hereinafter referred to as ‘3D image’).
2. Discussion of the Related Art
Recently, image display devices may selectively implement a 2D image and a 3D image due to the development of various contents and circuit technology. The image display device implements the 3D image using a stereoscopic technique or an autostereoscopic technique.
The stereoscopic technique, which uses a parallax image between left and right eyes of a user with a high stereoscopic effect, includes a glasses type method and a non-glasses type method, both of which have been put to practical use. In the non-glasses type method, an optical plate such as a parallax barrier for separating an optical axis of the parallax image between the left and right eyes is generally installed in front of or behind a display screen. In the glasses type method, left and right eye images each having a different polarization direction are displayed on a display panel, and a stereoscopic image is implemented using polarized glasses or liquid crystal (LC) shutter glasses.
An LC shutter glasses type image display device alternately displays a left eye image and a right eye image on a display element every one frame and opens and closes a left eyeglass and a right eyeglass of LC shutter glasses in synchronization with a display timing, thereby implementing the 3D Image. The LC shutter glasses open only the left eyeglass during odd-numbered frame periods, in which the left eye image is displayed, and open only the right eyeglass during even-numbered frame periods, in which the right eye image is displayed, thereby making binocular disparity in a time division method. In the LC shutter glasses type image display device, because the LC shutter glasses are turned on in a short period of time, the luminance of the 3D image is low. Further, an extreme amount of 3D crosstalk is generated because of the synchronization between the display element and because of the LC shutter glasses and the On/Off conversion response characteristic.
As shown in FIG. 1, a polarized glasses type image display device includes a patterned retarder 2 attached to a display panel 1. The polarized glasses type image display device alternately displays left eye image data L and right eye image data R on the display panel 1 every one horizontal line and converts polarization characteristics of light incident on polarized glasses 3 using the patterned retarder 2. Through such an operation of the polarized glasses type image display device, a left eye image and a right eye image may be spatially divided, thereby implementing a 3D image.
In the polarized glasses type image display device, because the left eye image and the right eye image are adjacently displayed on the adjacent horizontal lines of the display panel 1, the range of a vertical viewing angle, in which a crosstalk is not generated, is very narrow. The crosstalk is generated when a doubled image of the left eye image and the right eye image is displayed at a location of the vertical viewing angle. To prevent the crosstalk in the polarized glasses type image display device, as shown in FIG. 2, a method for forming black stripes BS in an area of a patterned retarder 2 to thereby widen a vertical viewing angle of the 3D image had been proposed, for example, in Japanese Laid Open Publication No. 2002-185983. However, the black stripes BS of the patterned retarder 2 used to widen the vertical viewing angle cause side effects resulting in a large reduction in a luminance of a 2D image.